Prof. Dr. Jihyun Hwang holds a PhD in offshore cryogenic liquefaction process optimization from graduate school of Seoul National University, South Korea. He is an experienced Hydrogen, LNG, Oil & Gas process professional who brings 24 years of relevant experience to specific projects and technology development. He is a Professor, Head of Hydrogen Energy at KENTECH (https://www.kentech.ac.kr), a managing director for FIP (Fraunhofer InnovationPlatform) H2Energy@KENTECH (FIP-H2ENERGY@KENTECH) as well as Head of the HYLOT R&D lab (https://hylot.kentech.ac.kr), specialized in Hydrogen & LNG processes and project engineering. Before joining KENTECH, Prof. Dr. Jihyun Hwang worked as an expert in different international companies in South Korea, the United States, the Netherlands, and Germany. He is an esteemed technology development leader for (floating and onshore) hydrogen production & storage projects with in-depth knowledge and technical expertise in process engineering for cryogenic processes (Hydrogen, LNG) and liquefaction engineering, natural hydrogen, blue hydrogen, green and blue ammonia, methanol production, and CCUS (Carbon Capture Utilization and Storage).

This lecture introduces the principles and applications of hydrogen liquefaction, with a focus on cryogenic process design and future large-scale development. First, fundamental concepts of cryogenic thermodynamics and typical process configurations for ultra-low temperature systems are reviewed. Second, current precooling practices in commercial hydrogen liquefaction plants, which commonly rely on liquid nitrogen (LN₂), are discussed, and alternative precooling concepts utilizing LNG cold energy or LNG-based refrigeration cycles are presented as promising options for future large-capacity plants. Finally, liquefier process configurations based on the Claude cycle using hydrogen as the refrigerant are examined, with emphasis on technical challenges and strategies for large-scale capacity application, energy efficiency improvement, and integration with emerging hydrogen infrastructure.

John Weisend is a Senior Accelerator Engineer at the European Spallation Source specializing in large scale cryogenics and He II. He is the Chair of the Cryogenic Society of America and the International Cryogenic Engineering Conference Board. He is Editor-in-Chief of the journal Interactions. His books include: Superfluid, He is for Helium, The Handbook of Cryogenic Engineering (ed), Cryostat Design (ed), and Cryogenic Safety (with T. Peterson).

Cryogenics is an enabling technology in accelerators, high energy physics and fusion energy. In many cases, work in these fields is only possible at cryogenic temperatures. Cryogenics is used to cool superconducting magnets, superconducting RF cavities, provide dense pure liquids for moderators, targets and particle calorimeters and at sub-Kelvin temperatures to provide environments for the detection of rare events and dark matter. Over the years, innovations in these fields and in large scale cryogenics have fed into each other; resulting in new technologies and scientific discoveries.
This class will survey the use of cryogenics in accelerators, high energy physics and fusion energy. It will describe motivations, the innovations developed and give examples of many systems. The features of large scale cryogenic plants will also be described.